Polyphenylene ether resins generally show outstanding mechanical properties, thermal resistance, electrical characteristics, and flame resistance and are commonly used in a broad range of applications such as components in automobiles. In particular, various internal components in automobiles such as, e.g., instrument panels, arm rests, and top covers, require a high degree of thermal resistance making polyphenylene ether resin compositions ideally suited. Many of these same internal components are covered with a foamed polyurethane due to its desirable characteristics; however, polyphenylene ether resin compositions ordinarily have poor adhesion to foamed polyurethane.
Various methods have been developed to enhance the adhesive properties between polyphenylene ether resin compositions and foamed polyurethane. For example, U.S. Pat. No. 5,370,813 describes the addition of various primary and secondary amines to compositions of polyphenylene ether resin and alkenyl aromatic resins. Although adhesion is significantly enhanced, unpleasant “ammonia-like” odors have been reported due to the amines under abusive molding conditions.
In Japanese Unexamined Patent Application H2-199164, terpene phenol resin has been added compositions of polyphenylene ether resin and alkenyl aromatic resins; however, the adhesive properties of these compositions are still deficient. Various polar resins, e.g., styrene-maleic anhydride copolymer have also been used in compositions of polyphenylene ether resin and alkenyl aromatic resins with limited success due to laminar peeling during molding and decreased mechanical properties. EP 0808871 discloses a resin composition of polyphenylene ether and polystyrene with enhanced adhesion and reduced laminar peeling from polyurethane brought about by the use of an ethylene-unsaturated carboxylic acid ester copolymer. However, in spite of the various methods of the prior art there remains a need for improved methods and compositions for enhanced adhesion of polyphenylene ether resin compositions with polyurethane foam.